The disclosure relates to a method and a device for the transport of toner material from a reservoir. Toner material is conveyed away from an extraction opening of the reservoir via an air current. The disclosure also concerns a tube-shaped conduit for the transport of toner material and a sealing device to seal a reservoir via which a simple extraction of toner material from the reservoir is possible.
In electrophotographic printers or copiers, a latent charge image is generated on a light-sensitive photoconductor material, a photoconductor drum or a photoconductor band. This charge image is subsequently inked with electrically-charged toner in a developer station of the printer or copier. The inked toner image is subsequently transferred to a carrier material, for example paper, and is fixed on this.
A one-component developer or a two-component developer is used to develop the latent charge image in the developer station. The one-component developer comprises only toner particles; the two-component developer comprises a mixture of toner particles and carrier particles. In the two-component developer, the toner particles are electrically charged via movements of the two-component developer mixture. In the one-component developer, the charging of the toner particles occurs via charge transport, for example by a carrier roller.
The toner quantity necessary: to generate the toner image must be supplied to the developer station in order to be able to generate further toner images. In known printers or copiers, near the developer station a temporary storage for toner material is provided from which toner material is transported into the developer station as needed or as requested.
In known printers or copiers, the temporary storage is filled with toner material from handy toner transport reservoirs through an opening directly into the reservoir, or is conveyed into the temporary storage via a transport system from a separately arranged transport reservoir. In known printers or copiers, the temporary storage near the developer station has a fill level sensor. Given a minimal fill level, toner material must be supplied to the temporary storage from the toner transport reservoir. This occurs, for example, via emptying a transport reservoir into the temporary storage. In other known arrangements, sealed reservoirs filled with toner material and in the form of bottles or cartridges are adapted to an opening in the temporary storage. The bottle or cartridges is opened by pulling a slider and/or ripping open a flap, whereby the toner material can fall into the reservoir.
However, in these solutions to refill toner material into the temporary storage, a high danger of contamination exists for operating personnel and the environment of the temporary storage upon filling of the toner material and upon removal of the emptied transport reservoir. A low weight and a small structural size of the bottles and/or cartridges in fact enables a simple manipulation and a safe handling upon refilling of the temporary storage. However, given a high toner usage a frequent refilling of the reservoir is necessary, whereby long machine downtimes are created and the operating personnel is severely stressed.
A toner reservoir and a device for contamination-free exchange of such a toner reservoir in a toner transport device of a printer or copier is known from the documents U.S. Pat. No. 4,990,964 and U.S. Pat. No. 5,074,342. Toner material is transported as needed from a toner reservoir arranged separate from the developer station into the temporary storage as needed via a tube, with the aid of suction air. A vertically displaceable suction spout is immersed through an opening arranged in the top of the toner reservoir and sucks toner material out. A special shaping of the toner reservoir and a laterally connected vibrating unit provide for a nearly complete emptying of the reservoir. The suction spout is drawn from the reservoir to exchange the reservoir. The opening in the toner reservoir is always arranged on top, whereby a spillage of toner is prevented. However, the conveying capacity is strongly dependent on the fill state in the toner reservoir. The conveying capacity also decreases with a reduction of the fill level, such that the printing event is interrupted given a low toner level in the reservoir and a simultaneously large toner requirement in the developer station. The vibrating unit also causes disturbing noises.
An apparatus to convey toner material from a reservoir by means of a suction and force unit that protrudes into the reservoir is also known from the document U.S. Pat. No. 5,915,154 or DE 196 52 860 A1. Toner material is interspersed with gas with the aid of the suction and force unit, such that the toner material to be vacuumed is mixed into a powder-gas mixture, whereby the suction of the fine-powder toner material from the reservoir is eased. However, the problem also occurs in this known device that the conveying capacity also decreases with a decrease of the fill level in the reservoir, and it leads to an already-described interruption of the print process as a consequence of a too-small toner material redelivery.
A device for the transport of toner material in which toner material is output from a reservoir onto a slanted plane is known from the document U.S. Pat. No. 5,884,126. The surface of the slanted plane comprises porous elements via which air penetrates from below through the surface to the toner material and intersperses the toner material with air, whereby a fluid-like mixture made of toner material and air forms. This mixture flows downwards on the slanted plane into a temporary toner storage. However, with such a known apparatus toner material can only be transported to lower-lying positions, whereby given this transport type it is also necessary to provide further means in order to prevent contaminations of the printer or copier upon transport of the toner material.
A device for the removal of toner material from a reservoir is known from the document U.S. Pat. No. 5,727,607. In this known device, air is pushed through air-permeable regions of the removal device into the toner reservoir with the aid of overpressure, whereby a toner-air mixture is created in the toner reservoir. The toner-air mixture falls downwards out of the reservoir through a removal opening into a capture device.